Answer:
The changes in the sequence of nucleotides present within a promoter is a prime cause of the defected transcriptional regulation, which may eventually result in disease. However, not every modification within the sequence of a promoter influences the regulation of transcription, it relies upon the nature and the location of the genetic defect.
When a mutation results within the sequence of a promoter region it may hamper the usual procedures of gene stimulation by affecting the step by step alignment of the transcription factors at the promoter region. Therefore, as a consequence, a mutation within the sequence of a promoter may result in the enhancement or reduction in the level of mRNA and thus protein.